savedsol

Can it be done? I've got a great line up on that size winter tires I need badly!

tdiddy

Wider is not better when it comes to winter tires. The best size for the stock wheels is 225/45/18.

Nemesis8

iTrader: (3)

I run Pirelli PZero Nero MS 245/40R18 on stocker rims, and they work pretty good on all surfaces.

TeamRX8

iTrader: (25)

255/40-18 is taller and wider though. It will mount on the wheel ok, but it *may* rub under some conditions

I don't know this for a fact, it's a concern, especially if the car is lowered.

Using Blizzak specs:

255/40 VR18 10.3" section width 9.1" tread width 26.1" diameter

245/40 VR18 9.8" section width 8.8" tread width 25.7" diameter


Not to mention that for winter tires it's ideal to use a narrower width, ok to use the same width, and frowned upon to use a wider width as a general guide

savedsol

Why is narrower better? Wouldn't more contact patch = better grip?

Easy_E1

iTrader: (2)

For one thing a wider tire will displace the weight of the car over a wider area/surface of the tire/road. "POUNDS PER SQUARE INCH". Thus lowering the weight per square inch on the surface of the tread as it contacts the road surface. Thus making the car seem lighter. Lighter will have a tendancy to not provide as much friction (due to wieght lose per sq.inch)to the tread contact patch, end result is it will have a tendancy to spin more freely.
This works the opposite for dry conditions. Make sense?

pdxhak

iTrader: (2)

According to the tire calculater at discount tire they seem to be a fairly close in size. But I agree with other skinner tires would be better because less weight would be spread across the tire.

Tire 1 = 225/45/18
Tire 2 = 255/40/18

Totals are in inches Tire 1 Tire 2 Difference
Sidewall Height: 3.99 4.02 .03
Section Width: 8.86 10.04 1.18
Overall Diameter: 25.97 26.03 .06
Circumference: 81.59 81.78 .19
Revs per mile: 800.92 799.08 -1.84

If your speedometer reads: 65 You're going approximately: 65.15

savedsol

Yes indeed! Thank you all.

KRNrx8Driver

but if you stagger the wheels wont the ecu go insane like the traction control and stuff? cuz i was takling to a mazda service guy who had a guy with that problem because the abs and tcs notices that some wheels are spinnging at different speeds but then again his two different sizes was the passenger front and driver rear but ya...anywayz also if you do get wider tires is there a way to reset the ecu so that it calculates the spedometer and the odometer to match the new wheel size?